In a number of industrial applications it is well known to heat drums of liquid material from a storage temperature to a usable temperature, with the use of filament heaters for purposes of this type being commonplace. As an alternative, steam may be utilized for heating drums of material, for by such a means as this, the contents of a drum can be rapidly brought up to a desired temperature.
Although various provisions are made for ostensibly protecting the contents of a drum from overheating, from time to time there is a degree of equipment failure, or the erroneous settings of the maximum temperature to which the contents of the drum will be subjected, in which case the drum and its contents may become overheated. An overheated drum may represent merely the loss of the contents thereof, or in case the drum contains a toxic or potentially toxic substance, the overheating of the drum may provide a distinct hazard to personnel as well as to the building in which the drum is being heated.
It was to overcome the disadvantages of prior art arrangements of this type that the present invention was evolved.